Dynamically applying refresh overcharge voltage to extend refresh cycle time

Abstract

A refresh voltage control engine selectively applies different high voltages to use in refresh operations. The control engine can detect that a portion of a memory device needs to be refreshed, and determine that the refresh cycle time is too short for a state of the portion of the memory device. The memory device typically has an associated refresh cycle time or time between refreshes based on the device and system architecture. The control engine can generate one or more control signals to cause the system to apply an overcharge refresh to overcharge the portion of the memory device with a refresh operation to extend the refresh cycle time for the portion of the memory device.

What is claimed is: 
     
       1. A method for managing memory device refresh, comprising:
 detecting that a portion of a memory device needs to be refreshed, the memory device having an associated time between refreshes; 
 determining whether the time between refreshes is too short for a state of the portion of the memory device; and 
 if the time between refreshes is too short for the state, applying an overcharge refresh with an overcharge voltage to the portion of the memory device with a refresh operation to selectively extend the time between refreshes for the portion of the memory device; otherwise, 
 applying a refresh operation with a refresh voltage that does not extend the time between refreshes for the portion of the memory device. 
 
     
     
       2. The method of  claim 1 , wherein determining that the time between refreshes is too short for the state comprises determining that the memory device is in a low power state. 
     
     
       3. The method of  claim 1 , wherein determining that the time between refreshes is too short for the state comprises determining that the portion of the memory device stores data designated to have a longer time between refreshes. 
     
     
       4. The method of  claim 1 , wherein applying the overcharge refresh for the portion of the memory device comprises applying the overcharge refresh for the portion of the memory device, but not for another portion of the same memory device. 
     
     
       5. The method of  claim 1 , wherein applying the overcharge refresh further comprises sending an overcharge refresh command from a memory controller to the memory device, wherein the memory device receives an external overcharge refresh voltage for the refresh operation. 
     
     
       6. The method of  claim 1 , wherein applying the overcharge refresh further comprises sending an overcharge refresh command from a memory controller to the memory device, wherein the memory device generates an overcharge refresh voltage for the refresh operation. 
     
     
       7. The method of  claim 1 , wherein applying the overcharge refresh for the portion of the memory device further comprises setting time between refreshes for auto refresh operations. 
     
     
       8. The method of  claim 1 , wherein applying the overcharge refresh for the portion of the memory device further comprises performing the refresh operation with one of multiple different levels of overcharge refresh voltage. 
     
     
       9. An apparatus for dynamically applying a refresh voltage, comprising:
 control logic to detect that a portion of a memory device needs to be refreshed, determine whether a time between refreshes is too short for a state of the portion of the memory device, and if the time between refreshes is too short for the state, generate control signals to circuits that control refresh to cause the circuits to apply an overcharge refresh to overcharge the portion of the memory device with a refresh operation having an overcharge voltage to the portion of the memory device with a refresh operation to selectively extend the time between refreshes for the portion of the memory device; otherwise, to apply a refresh operation with a refresh voltage that does not extend the time between refreshes for the portion of the memory device; and 
 a high voltage selection circuit to selectively provide an overcharge voltage to the portion of the memory device to overcharge the portion of the memory device in response to a control signal from the control logic. 
 
     
     
       10. The apparatus of  claim 9 , wherein the control logic is to determine that the time between refreshes is too short because the memory device is in a low power state. 
     
     
       11. The apparatus of  claim 9 , wherein the control logic is to determine that the time between refreshes is too short because the portion of the memory device stores data designated to have a longer time between refreshes. 
     
     
       12. The apparatus of  claim 9 , wherein the control logic is to generate control signals to overcharge the portion of the memory device, but not another portion of the same memory device. 
     
     
       13. The apparatus of  claim 9 , wherein the control logic is part of a memory controller associated with the memory device. 
     
     
       14. The apparatus of  claim 9 , wherein the control logic is part of the memory device. 
     
     
       15. The apparatus of  claim 9 , wherein the control logic is to generate control signals to set a time between refreshes for auto refresh operations. 
     
     
       16. The apparatus of  claim 9 , wherein the high voltage selection circuit is to selectively provide one of multiple different levels of overcharge refresh voltage. 
     
     
       17. A system comprising:
 a refresh voltage control circuit, including
 control logic to detect that a portion of a memory device needs to be refreshed, determine whether a time between refreshes is too short for a state of the portion of the memory device, and if the time between refreshes is too short for the state, generate control signals to circuits that control refresh to cause the circuits to apply an overcharge refresh to overcharge the portion of the memory device with a refresh operation having an overcharge voltage to the portion of the memory device with a refresh operation to selectively extend the time between refreshed for the portion of the memory device; otherwise, to apply a refresh operation with a refresh voltage that does not extend the time between refreshes for the portion of the memory device; and 
 a high voltage selection circuit to selectively provide an overcharge voltage to the portion of the memory device to overcharge the portion of the memory device in response to a control signal from the control logic; and 
 
 a high-definition display coupled to generate a display based on data stored in the memory device. 
 
     
     
       18. The system of  claim 17 , wherein the control logic is to determine that the time between refreshes is too short because the memory device is in a low power state or because the portion of the memory device stores data designated to have a longer time between refreshes. 
     
     
       19. The system of  claim 17 , wherein the control logic is to generate control signals to overcharge the portion of the memory device, but not another portion of the same memory device. 
     
     
       20. The system of  claim 17 , wherein the high voltage selection circuit is to selectively provide one of multiple different levels of overcharge refresh voltage.